Railway signaling



April 6, 1937. R. A. MCCANN RAILWAY SIGNALING Filed Feb. 15, 1956 Patented Apr. 6, 1937 YUNITED STATES ,PATENT oFFicE RAILWAY SIGNALING Application February 15, `1936, Serial No. 64,094

13 Claims.

My invention relates to railway signaling, and particularly to signaling involving wayside signals located along a trackway for governing the passage of trains.

A feature of my invention is the provision of novel and improved apparatus for establishing a distinctive control for each of three sections in the rear of an occupied section. Each distinctive control is effective to cause a corresponding aspect of the associated wayside signal, whereby there is produced a three-block, four-indication, system of signaling.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic View illustrating one form of apparatus embodying my invention.

Referring to the drawing, the reference charaoters 8 and 9 designate the rails of a stretch of railway track along which tralc normally moves in the direction indicated by the arrow. These rails are divided by insulated joints I4 into a plurality of track sections W-X, X-Y, and Y-Z.

Each track section is divided by `insulated joints I4 into at least two subsections IT, 2T, 3T, 4T, etc. Each subsection is provided with a track circuit which includes a track battery I5 connected across the rails at one end of the subsection and a track relay, designated by the reference character R with a prex the same as the reference character of the associated subsection, connected across the rails at the other end of the subsection.

To govern the passage of trains through the stretch of railway, a wayside signal designated by the reference character S with a suitabledistinguishing prex is providedffor each track section. Each of these signals comprises a top unit T and a lower unit L. These units may take any one of several forms of signal mechanism such as semaphore, color light, searchlight, or position light. As here shown, each top unit is a semaphore arm capable of assuming a horizontal or stop position, a 45 or caution position, and a vertical or proceed position; and each bottom unit is a semaphore arm capable of assuminga horizontal or stop position and a vertical or proceed position.

Each section is provided with a polarized signal control line relay designated by the reference character HD with a prefix the same as the prex in the reference character of the associated signal.

Each section is also provided with a neutral signal control line relay designated by the reference character H with a `preiix the same as the prefix in the reference character of the associated signal.

Each polarized signal control relay HD is directly connected to a polarized line circuit which is controlled by the track relays of the section with which the polarized relay is associated as well as by the `Hlrelay and `HD relay of the sec- 10 tion in advance.

Each neutral signal control relay H is also provided with a polarized line circuit, one wire of which `is common to the line circuit for the associated `polarized relay. Each relay H is con- 15 nected to its polarized :line circuit through an asymmetric unit, here shown as a full wave rectifier, and designated by the reference character Q with av prefix the same as the prefix of the associated neutral relay. It will be readily apparent that although the relays H are connected topolarized circuits, these relays, due to the valve action of the rectifiers, will be energized in the same direction regardless of the polarity of the line current.

It will be noted ,that each rectier Q is connected Vto its line circuit through a resistor desighated by the reference character P with a prex the same was `the prefix of the associated reotier. The resistors Pare connected in the line circuits to prevent excessive current flow in the event of the associated rectifier becoming short-circuited.

It will ,also be noted that since one line wire is common tobothpolarizedline circuits, onlythree line wires are required between signals. 35

The manner in which the signals `are controlled to cause the `display of thedifferent aspects will best be understood by tracing the circuits and explaining the operation of the apparatus simultaneously. 40

A train is indicated `diagrammatically at K in the subsection IT immediately to the vright of location Z. The train shunt of train vK will deenergize the track relay -ITR in the usual manner. Both line relays I 3Hwand I SHD will be without energy due to front contacts I6, Il, and I8 of relay TTR being opened. The signal I 3S, therefore,Y is displaying `both its semaphore` arms `in the horizontal position to indicate stop.

The Yrelay IZH forsignal I2S is energized over 50 a line `circuit which passes from terminal B of `a suitable sourceof current, at signal i3, through back point of contact 2| ,of relay `I3I1l2D, front contact 22ofre1ay GTR. wire 22A, frontcontact 23 of track relay 5TH, resistor I 2P, rectifier IZQ, 55

relay I2H, front Contact 24 of relay ETR, wire 24A, front contact 25 of relay STR, and back point of contact 26 of relay I3HD to terminal C of the same source of current.

Since relay I2H is energized and relay I2HD is deenergized, top semaphore T of signal I2S is energized over a caution circuit which passes from terminal B through front contact 28 of relay I2H and semaphore T to terminal C. The signal I2S, therefore, is displaying its top semaphore arm in the position and its lower semaphore arm in the horizontal position to indicate approach next signal prepared to stop.

The relay III-I for signal IIS is energized over a line circuit which passes from terminal B, at signal I2, through back point of contact 3|) of relay I2HD, front contact 3l of relay 4TR, wire 32, front contact 33 of track relay STR, resistor IIP, rectier IIQ, relay III-I, front contact 34 of relay STR, Wire 35, front contact 36 of relay 4TR, and back point of contact 31 of relay I2HD -to terminal C. Relay IIHD is energized in the reverse direction over a line circuit which passes from terminal B, at signal I2, through back point of contact 3G of relay lZHD, iront contact 3| of relay 4TR, wire 32, front contact 33 of relay STR, relay IEHD, front contact 38 of relay 3TR, wire 39, front contact 4G or relay 4TR, front Contact 4I of relay IZH, and back point of contact 31 of relay. I 2HD to terminal C.

Since relay I IH is energized and relay I IHD is energized in the reverse direction, the caution circuit for the top semaphore T of signal IIS will remain closed over a path which passes from terminal B through front contact 42 of relay l IH and semaphore T of signal IIS to terminal C; and a proceed circuit for the lower semaphore L of signal IIS is energized over a path which passes from terminal B through front contact 43 of relay IIHD, reverse polar contact 44-45 of relay HD, and lower semaphore L of signal IIS to terminal C. Signal IIS, therefore, is displaying its top semaphore arm T in the 45 position and its lower semaphore arm L in the vertical positionV to indicate approach next signal at medium speed. l

The relay IDH for signal IUS is energized over a line circuit which passes from terminal B, at signal I I, through front point of contact 46 of relay III-l1), front contact 41 of relay 2TR, wire 48, front contact 49 of relay ITR, rectifier IIlQ, relay IUH, resistor IUP, iront contact 50 of relay ITR, wire 5I, front contact 52 of relay ZTR and front point of contact 53 of relay I IHD to terminal C. Relay IHD is energized in the normal direction over a line circuit which passes from terminal B, at signal II, through front point of contact 46 of relay IIHD, front contact 54 of relay IIH, front contact 55 of relay 2TR, Wire 56, front contact 51 of relay ITR, relay IUHD, and thence to terminal C through front contact 50 of relay ITR over the same path as just described for relay IlH.

Since relay IIlHis energized and relay IilI-ID is energized in the normal direction, the caution circuit for the top semaphore T of signal IOS will remain closed over a path Which passes from terminal B through front contact 58 of relay IUH and semaphore T to terminal C, and a proceed circuit for the top semaphore T is closed over a path which passes from terminal B through front contact 5B of relay IDHD, normal polar contact 44-60 of relay IIIHD and semaphore T to terminal C.

Signal IIJS, therefore, is displaying its top semaphore arm T in the vertical position and its lower semaphore arm L in the horizontal position to indicate proceed at normal speed.

Since both relays IDH and I HD are energized, it will be apparent that both line circuits for the section next in rear of location W, are energized by current of proper polarity so that the signal (not shown) controlled by such rear line circuit is displaying the normal proceed indication.

When the train K vacates the section immediately to the right of location Z, relay I2HD will become energized in the reverse direction so that relay IIHD will become energized in the normal direction to cause signal I I to display the normal proceed indication.

From the foregoing description it is apparent that I have provided a simple and reliable means for controlling a three-block, four-indication, signaling system which requires but three line control wires between signals, and which requires direct current energy only.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track having a track circuit including a track relay, a signal for said section capable of assuming several distinctive aspects, a polarized line relay and a neutral line relay for jointly controlling the different aspects of said signal, a first polarized line circuit including a contact of said track relay for governing said polarized relay in accordance with trailc conditions in advance of said section, a second polarized line circuit including a co-ntact of said track relay as well as a portion of said rst line circuit for governing said neutral relay,and a rectier for connecting said neutral relay to Vsaid second polarized line circuit thereby preventing the release of said neutral relay during pole changing periods.

v2.*In combination, a stretch of railway track, a signal for said stretch capable of assuming several distinctive aspects, a polarized line relay and a neutral line relay for jointly controlling the different aspects of said signal, a polarized line circuit for governing said polarized relay in accordance with traic conditions in advance of said signal, another polarized line circuit including a portion of the first polarized line circuit for governing said neutral relay in accordance with traic conditions in advance of said signal, and an asymmetric unit for connecting said neutral relay to said other polarized line circuit.

3. A railway signal system comprising, a stretch of railway track divided into a plurality of track sections each having a track circuit including a track relay, a first line circuit for each section controlled by the associated track relay, a secondline circuit for each section also controlled by the associated track relay, a polarized relay for said first line circuit, a neutral relay for said second line circuit, means controlled by each polarized relay for supplying current to the second linecircuit for the section next in rear for controlling the neutral relay of that line circuit, means controlled jointly by the polarized relay and the neutral relay of each section for reversibly controlling the iirst line circuit for the section next in rear for controlling the polarized relay of that line circuit, `and traffic governing vmea-ns :for governing the passage of 'trains along said stretch controlled by saidpolarizedandneutral relays.

4,. A railway signal system comprising a stretch of railway `track divided into sections each having a track Ycircuit including a track relay, two relays for each section, a first line circuit for controlling one of said relays and including a contact of the track relay for the section with which said one relay is associated, .a second line circuit for controlling the other of `said rela-ys and also lincluding a contact of `said track relay, means controlled by said two relays for reversibly supplying current to the rst lline circuit for the sectionnext in rearofpthe associated section, means controlled by one of said relays for supplying current to the second line circuit for the section `next in rear of the associated section, and signaling means for each section controlled jointly by said two relays of the section.

5. A railway signal system comprising, a stretch of railway track divided into sections, two polarized line circuits for each section controlled by traffic conditions in advance of the associated section, a polarized relay for each section and connected to one line circuit of the associated section, a neutral relay for each section and connected through a rectier to the other of the line circuits of the associated section, and signaling means for each section controlled jointly by said two relays of the section.

6. A railway signal system comprising; a first, a second and a third consecutive track section over which traffic normally progresses in the order named; a polarized line relay and a neutral line relay for each section, means controlled by a train occupying the third section effective to deenergize both the polarized and neutral relays of that section, means effective to deenergize the polarized relay for the second section when the neutral relay for the rst section is deenergized, means for energizing the neutral relays for both the second and first sections as long as said second and rst sections are unoccupied, means for energizing in the reverse direction the polarized relay for the rst section, said means being effective when the polarized relay for the second section is deenergized `and the neutral relay for the second section is energized, a signal for the third section caused to indicate stop when both its polarized and neutral relays are deenergized, a signal for the second section caused to indicate a restrictive indication when its polarized relay is deenergized and its neutral relay is energized, and a signal for the first section caused to indicate a less restrictive indication when its polarized relay is energized in the reverse direction and its neutral relay is energized.

7. A railway signal system comprising; a first, a second, a third and a fourth track section over which trahie normally progresses in the order named; a polarized line relay and a neutral line relay for each section, means controlled by a train occupying the fourth section effective to deenergize both the polarized and neutral relays of that section, means for deenergizing the polarized relay for the third section when the neutral relay for the fourth section is deenergized, means for energizing the neutral relays for the first and second as well as the third section as long as said sections are unoccupied, means for energizing the polarized relay for the second section in the reverse direction when the neutral relay for the third section is energized and the ,polarized relay for the third section is deenergized, means `for energizing the polarized relay for the first section in the normal direction when the neutral relay and the polarized relay for the second section are both energized, `and signaling means controlled by the `lastrmentioned relays.

8. A railway signalsystem comprising, a stretch of railway track divided into sections each having a .track circuit including a Atrack relay, two `line relays for. each section one polarized and one neutral, a line circuit for governing each polarized relay and another line circuit for governing each neutral relay, both said `line circuits including a contact of the track relay for the section with which said line relays are associatedmeans controlled'by said two line relays for selectively supplying current of normal or reverse polarity or vsupplying no current to the line circuit for governlng the polarized relay for the section next in rear, means controlled by said polarized relay for supplying current to the line circuit for governing the neutral relay for the section next in rear, and a signal controlled by said two line relays of a section and arranged to have a first aspect when both relays are deenergized, a second aspect when the polarized relay is deenergized and the neutral relay is energized, a third aspect when the polar-l ized relay is energized in the reverse direction and the neutral relay is energized, and a fourth aspect when the polarized relay is energized in the normal direction and the neutral relay is energized.

9. A railway signal system comprising; a first, a second and a third track section over which traffic normally progresses in the order named, two line relays for each section one polarized and one neutral, means including a track relay for deenergizing both line relays for the third section when that section is occupied by a train, means for deenergizing the polarized relay of the second section and for energizing the neutral relay of the second section when both line relays of the third section are deenergized, means for energizing the polarized relay for the rst section in the reverse direction when the polarized relay for the second section is deenergized and the neutral relay for` the second section is energized, a signal for said rst section, and means including a reverse polar contact of the polarized relay for the first section for causing said signal to display an aspect indicating that the third section is occupied.

10. A railway signal system comprising, a stretch of railway track divided into track sections each such section having a track circuit including a track relay, a first polarized line circuit for each section and comprising two line wires, a second polarized line circuit for each section including another line wire and one of the line wires of the associated rst polarized line circuit, a polarized line relay connected to each said first line circuit, a neutral line relay connected to each said second line circuit through a rectifier, and means including the associated track relay for governing both said rst and said second line circuits for each section whereby a distinctive control is effected for each of three consecutive track sections to the rear of an occupied section.

11. In combination, a section of railway track, a signal for said section, a polarized line relay for controlling said signal, a polarized line cirby another polarized line circuit, traflic controlled means for governing said two line circuits, and means for maintaining the energize..-

tion of said neutral relay in one direction regardless of the polarity of said other line circuit thereby preventing the release of said neutral relay during pole changing periods.

12. In combination, a section of railway track, a signal for said section, a polarized line relay for controlling said signal, a rst polarized line circuit for governing said polarized relay, a second polarized line circuit which changes its polarity when the polarity of said i'lrst line circuit is changed, a neutral relay also for governing said signal and governed by said second polarized line circuit, and a rectifier for connecting said neutral relay to said second polarized line circuit thereby preventing the release of said neutral relay during pole changing periods.

13. In combination, a section of railway track,

two relays onepolarized and one neutral, a polarized line circuit and a neutral line circuit for governing said polarized and neutral line relays respectively, track circuit means for governing both said line circuits, means for energizing said neutral line circuit, means including a pole changer governed in'accordance with trafiic conditions in advance of said section for governing said polarized line circuit, a signal for said section including a irst indication unit and a second indication unit, a circuit for said rst unit including only a front contact of said neutral relay, another circuit for said first unit including only a front neutral contact and a normal polar contact both of said polarized relay, and a circuit for said second unit including a front neutral and a reverse polar contact both of said polarized relay.

RONALD A. MCCANN. 

